What Is Strep Throat? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Strep throat is a bacterial infection that can cause a sore, scratchy throat. The infection mostly affects children ages 5 to 15, but anyone can get it. (1)

Caused by bacteria known as Streptococcus pyogenes (Group A streptococcus), strep throat (streptococcal pharyngitis) is spread by secretions from an infected person’s respiratory tract — often transmitted in droplets when that person coughs or sneezes. (1)

While strep throat is prevalent in school-age children, it’s not the most common cause of a sore throat. (2) Infections caused by a virus are much more likely to be the culprit.

While you or your child may recover from a sore throat without treatment, it’s important to get tested for strep if you suspect it might be causing your symptoms. (1)

If strep throat isn’t treated promptly with antibiotics, it can lead to complications, including abscesses near the tonsils, infected lymph nodes, or a serious inflammatory condition called rheumatic fever. (1)

Symptoms of strep throat include the following: (3)

• Sore throat
• Red swollen tonsils
• White patches in the back of your throat
• Fever
• Nausea
• Headache
• Body aches
• Skin rash

Many of these symptoms overlap with those of a viral infection. If you have any of these symptoms along with a runny nose or a cough, it’s more likely to be a viral infection, such as a common cold. (4) There can also be overlap between symptoms of strep throat and those of COVID-19, which is caused by a type of coronavirus.

When you experience a sore throat due to a cold, it often gets better or goes away after a day or two. With strep, the sore throat persists and is often more severe. (5) Bronchitis, a lower respiratory infection caused by cold and flu viruses, can often be accompanied by a sore throat as well. (6)

If you’re not sure what’s causing your symptoms, it’s best to see your doctor for a diagnosis.

Learn More About Signs and Symptoms of Strep Throat

Anyone can get strep throat. But you’re more likely to become sick if: (3)

• You’re between 5 and 15 years old
• It’s winter or early spring, when large groups of people tend to crowd together in enclosed environments, spreading bacteria

Since strep throat is contagious, you’re much more likely to catch it if you’re in close contact with someone who is infected. (7)

According to Nipunie S. Rajapakse, MD, a pediatric infectious disease specialist at the Mayo Clinic, strep infections commonly spread in households with more than one child, as well as in schools and childcare centers.

“Within a household, you may be sharing utensils or drinks,” Dr. Rajapakse notes. “It’s not uncommon that we’ll see two kids from the same family with similar symptoms at the same time.”

While it’s rare for adults to catch strep throat, it’s not impossible — especially if they work in a school or childcare setting.

“We do know that adults that work closely with kids tend to be exposed and get infected more commonly than the general population,” Rajapakse notes.

If you suspect that you or your child may have strep throat, you should make an appointment with your doctor as soon as possible. (8)

Your doctor will conduct a physical exam, looking for signs and symptoms of strep throat.

The only way for your doctor to diagnose strep throat is to perform either a rapid antigen test or a throat culture. Both involve rubbing a sterile swab over the back of the throat and tonsils to get a sample of the secretions. (8)

Usually your doctor will perform the rapid antigen test first. This test can detect strep bacteria in minutes by looking for substances (antigens) in the throat. (8)

If the test comes back negative but the doctor still suspects strep, the next step might be a throat culture. (8) Some doctors will do both tests at the same time based on local protocols.

Samples collected from the back of the throat are cultured in a laboratory to reveal the presence of bacteria. Results of a throat culture can take as long as two days. (8)

With proper treatment, strep throat usually goes away within 10 days. (9)

Antibiotics typically relieve symptoms in a day or two. (8)

Strep throat is highly treatable with prescription drugs. Over-the-counter medicines and home remedies can help relieve symptoms, but they can’t cure the underlying infection.

Medication Options

Since strep throat is a bacterial infection, it requires antibiotics. Common antibiotics include penicillin (Bicillin L-A) and amoxicillin (Amoxil), which can be taken orally or via injection. (9)

Although symptoms will improve pretty quickly, it’s important to take the full course of medication to completely kill the bacteria and prevent complications. (9)

Along with antibiotics, regular over-the-counter medications, such as acetaminophen (Tylenol) or ibuprofen (Advil), can help to relieve pain. Sucking on throat lozenges also provides effective temporary relief. (2)

Alternative and Complementary Therapies

Home remedies can’t cure strep throat, but they can combat discomfort. Simple solutions, like drinking tea with honey and lemon or gargling with warm salt water, can soothe symptoms and even reduce swelling. (2) Cold foods, such as ice pops and ice chips, work to numb pain, too.

You can also use a vaporizer or humidifier, which adds moisture to the air. This calms a dry, painful sore throat and eases congestion. (2)

Learn More About Treatment for Strep Throat: Medication, Alternative and Complementary Therapies, and More

Prevention of Strep Throat

Strep throat is highly contagious. When people with the infection cough or sneeze, they spread the bacteria through airborne droplets. You can get strep throat by touching surfaces that carry the bacteria, like door handles, and then transferring this bacteria to your eyes, nose, or mouth. (3)

To stay healthy, you should wash your hands and your child’s hands regularly, particularly after coughing or sneezing and before you prepare food or eat. (10) Carry a bottle of hand sanitizer with you to kill bacteria when you’re on the go. You should also wash glasses, utensils, and plates after someone who is sick uses them. (10)

If you are sick, taking antibiotics prescribed by your doctor reduces the risk of transmission. (7)

“We know that it takes about 24 hours of antibiotics before you cannot transmit strep anymore, so be especially careful during that period of time,” says Rajapakse. In practice, this means staying home from school, day care, or work until you no longer pose a risk to others. (7)

While you are contagious, remember to cover your mouth when you sneeze or cough, wash your hands frequently, and avoid kissing.

While not very common, complications can occur from a strep throat infection. This can happen if the bacteria spread to other parts of the body, causing so-called invasive infection.

Complications can include: (10)

• Abscesses (pockets of pus) around the tonsils
• Swollen lymph nodes in the neck
• Sinus infections
• Ear infections
• Post-streptococcal glomerulonephritis (a kidney disease)

Untreated strep throat can also cause rheumatic fever, a rare but serious infection that can cause damage to the heart (rheumatic heart disease). (11)

The link between strep infection and rheumatic fever isn’t clear, but it appears that the bacteria trick the immune system. The body’s immune system, which normally targets bacteria, attacks its own tissue instead, particularly tissues of the heart, joints, skin, and central nervous system. This results in inflammation or swelling that can last from a few weeks to several months. (11)

Acute rheumatic fever is exceedingly rare in the continental United States, with 0.04 to 0.06 cases per 1,000 children each year. (12) The rate is higher in Hawaii, with as many as 0.1 cases per 1,000 children each year, and an even higher rate exists among Hawaiian residents of Samoan origin.

There are several million cases of strep throat and other diseases associated with Group A streptococcus bacteria in the United States each year. (13)

Out of these millions of cases, between 11,000 and 24,000 are invasive infections, meaning that the bacteria has spread to areas like the inner skin layers, blood, and lungs. (13)

Worldwide, strep throat affects more than 616 million people each year. (14)

The most dangerous potential complication of strep throat is acute rheumatic fever (ARF). There are approximately 470,000 new cases worldwide each year. (13)

While most of these cases occur in developing countries, certain Black, Indigenous, and People of Color (BIPOC) communities, including Indigenous communities in developed nations, appear to have higher incidence rates of the disease.

ARF is a significant cause of disease among Australia’s Aboriginal and Torres Strait Islander populations (who represent less than 3 percent of the country’s population), while it occurs very rarely among its other populations. (15)

Even more concerning, Indigenous Australians under the age of 35 in the Northern Territory are up to 122 times more likely to have rheumatic heart disease, the permanent damage to the heart muscle or heart valves that can result from ARF, than their non-Indigenous counterparts. (15)

Conditions related to strep throat include:

• Scarlet fever
• PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections)

Scarlet Fever

The same bacteria that causes strep throat can cause scarlet fever (also known as scarlatina). (16) This disease can occur when group A streptococcus produces a toxin that leads to the signature red rash.

Scarlet fever is generally a mild infection. It usually takes two to five days for someone exposed to group A strep to become sick.

The initial symptoms of scarlet fever are a fever and a sore throat. Symptoms may also include chills, vomiting or abdominal pain.

One or two days after the illness begins, a red and bumpy “strawberry-like” rash usually appears on the neck and chest, then spreads over the body. The rash fades in about 7 days. (16)

With proper antibiotic treatment (usually either penicillin or amoxicillin), symptoms get better fairly quickly. (16)

PANDAS

A small number of children may experience behavior changes following a strep throat infection, known as PANDAS, or pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections.

PANDAS occurs when the immune system mistakenly attacks the brain in response to a strep infection. (17) It results in OCD-like symptoms and body tics. These symptoms are usually dramatic and seem to happen “overnight and out of the blue.” Children may also become moody or irritable, experience anxiety attacks, or show concerns about separating from their parents or loved ones.

This diagnosis is controversial among doctors, as some don’t believe PANDAS exists.

Different Types of Strep Infection

The group A streptococcus bacteria that cause strep throat are responsible for the most common type of streptococcal infection, but Group B, C, and G streptococcal bacteria can also result in illness.

Group B Strep

Group B streptococcal bacteria can be found in the vagina or rectum of pregnant women. Although infection is usually harmless in adults, one can be passed on to babies during delivery and cause a serious illness, known as group B strep (GBS) disease.

All expectant mothers should receive a routine screening for GBS between 36 and 37 weeks of pregnancy.

Like strep throat, GBS is treated with antibiotics like penicillin. (18)

Groups C and G Strep

Group C and G streptococci are not as common as strep A and B. (19) These strains of strep are more likely to live in certain animals, such as horses and cattle. The foundation notes that humans can contract group C and G strep by drinking raw milk or coming into contact with an infected animal.

Group C and G streptococci can be treated with antibiotics. (19)

Learn More About the Different Types of Strep

Centers for Disease Control

The CDC site is a go-to for information on the prevention, diagnosis, and treatment of strep throat and all its related conditions.

Cleveland Clinic

Cleveland Clinic offers useful articles on all aspects of strep throat, from what you can expect when you visit your doctor to what to do if your child doesn’t seem to be improving even after taking antibiotics.

Mayo Clinic

Articles on the site of this highly-respected medical center are concise, easy to follow, and packed with details on all aspects of strep throat.

FamilyDoctor.org

This website offers helpful advice from the American Academy of Family Physicians, the only medical society devoted solely to primary care. Use their symptom checker tool to find a possible diagnosis for health issues, including strep throat. You’ll also find helpful lists of questions to ask your doctor.

PANDAS Network

This site is dedicated to improving the diagnosis and treatment of children with PANDAS, a confusing and often misunderstood disorder. It shares the latest research, information on new treatments, and medical providers across the country who treat PANDAS patients.

Additional Reporting by Barbara Kean.